A PRECURSOR TO TILE BURNING. DURING DIESEL ENGINE OPERATION, THE SPEED SUDDENLY DECREASES, THE LOAD INCREASES, THE ENGINE EMITS BLACK SMOKE, THE OIL PRESSURE DECREASES, AND A DRY FRICTION SOUND OF "CHIRPING" IS ANNOUNCED IN THE CRANKCASE, WHICH IS A PRECURSOR TO TILE BURNING. IN THIS SITUATION, THE MACHINE SHOULD BE STOPPED IMMEDIATELY, OTHERWISE IT WILL FURTHER AGGRAVATE THE WEAR OF THE BEARING SHELL, AND THE SURFACE OF THE SHAFT NECK WILL BECOME MORE SENSITIVE AND EXPAND. THE BEARING SHELL AND THE SHAFT NECK WILL QUICKLY BOND AND LOCK, AND THE ENGINE WILL SHUT DOWN.  THE PRECURSOR OF STICKING CYLINDER. CYLINDER STICKING USUALLY OCCURS IN DIESEL ENGINES WHEN THERE IS A SEVERE LACK OF WATER. BEFORE STICKING, THE ENGINE OPERATION IS WEAK, AND THE WATER TEMPERATURE GAUGE INDICATES OVER 100 ℃. A FEW DROPS OF COLD WATER ARE DRIPPED ONTO THE ENGINE BODY, MAKING A "HISSING" SOUND AND EMITTING WHITE SMOKE. THE WATER DROPLETS QUICKLY EVAPORATE. AT THIS TIME, THE ENGINE SHOULD BE OPERATED AT LOW SPEED OR IDLE TO REDUCE THE VEHICLE TEMPERATURE. IF THE ENGINE IS TURNED OFF IMMEDIATELY, IT WILL CAUSE THE PISTON AND CYLINDER LINER TO STICK TO THE CYLINDER.  THE PRECURSOR OF VALVE FALLING OFF THE CYLINDER. THE VALVE FALLING INTO THE CYLINDER IS GENERALLY CAUSED BY REASONS SUCH AS VALVE STEM BREAKAGE, VALVE SPRING BREAKAGE, VALVE SPRING SEAT CRACKING, AND VALVE LOCK CLAMP FALLING. WHEN THE CYLINDER HEAD MAKES A "DANG DANG" KNOCKING SOUND (PISTON TOUCHING VALVE), A "CHA CHA" FRICTION SOUND (PISTON TOUCHING VALVE), OR OTHER ABNORMAL SOUNDS ACCOMPANIED BY UNSTABLE ENGINE OPERATION, IT IS OFTEN A PRECURSOR TO THE VALVE FALLING OFF THE CYLINDER. AT THIS TIME, THE ENGINE SHOULD BE PARKED AND TURNED OFF IMMEDIATELY, OTHERWISE IT WILL DAMAGE THE PISTON, CYLINDER HEAD, CYLINDER LINER, AND EVEN BEND THE CONNECTING ROD, BREAK THE ENGINE BODY, AND BREAK THE CRANKSHAFT.  THE PRECURSOR OF POUNDING THE CYLINDER. TAMPING THE CYLINDER IS A HIGHLY DESTRUCTIVE MECHANICAL DISADVANTAGE, WHICH IS MOSTLY CAUSED BY LOOSENING OF THE CONNECTING ROD BOLTS, EXCEPT FOR THE VALVE FALLING OFF THE CYLINDER. AFTER THE CONNECTING ROD BOLTS LOOSEN OR STRETCH, THE CLEARANCE BETWEEN THE CONNECTING ROD BEARINGS INCREASES. AT THIS TIME, A "CLACKING" SOUND CAN BE HEARD AT THE CRANKCASE, WHICH INCREASES FROM SMALL TO LARGE. AT THE END, THE CONNECTING ROD BOLTS COMPLETELY FALL OR BREAK, AND THE CONNECTING ROD AND BEARING COVER ARE THROWN OUT, BREAKING THE BODY AND RELATED PARTS.  THE PRECURSOR OF A BROKEN AXIS. WHEN A HIDDEN CRACK OCCURS AT THE CRANKSHAFT NECK SHOULDER OF A DIESEL ENGINE DUE TO FATIGUE, THE SYMPTOMS OF THE DEFECT ARE NOT YET OBVIOUS. AS THE CRACK EXPANDS AND WORSENS, A MUFFLED KNOCKING SOUND IS ANNOUNCED IN THE ENGINE CRANKCASE. THE KNOCKING SOUND INTENSIFIES WHEN THE SPEED CHANGES, AND THE ENGINE EMITS BLACK SMOKE. SOON, THE KNOCKING SOUND GRADUALLY INCREASES, THE ENGINE SHAKES, THE CRANKSHAFT CRACKS, AND THEN IGNITES. THEREFORE, WHEN ABNORMAL DYNAMICS OCCUR IN THE ENGINE CRANKCASE, IT SHOULD BE STOPPED IMMEDIATELY FOR INSPECTION.  THE PRECURSOR OF FLYWHEEL FRACTURE. WHEN THERE ARE HIDDEN CRACKS IN THE FLYWHEEL, STRIKING IT WITH A HAMMER WILL MAKE A HOARSE SOUND. WHEN THE ENGINE IS OPERATING, THE FLYWHEEL WILL MAKE A KNOCKING SOUND, AND WHEN THE SPEED CHANGES, THE SOUND WILL INCREASE, CAUSING THE ENGINE TO SHAKE. IF THE MACHINE IS NOT STOPPED FOR INSPECTION AT THIS TIME, IT CAN EASILY CAUSE SERIOUS ACCIDENTS SUCH AS SUDDEN BREAKAGE OF THE FLYWHEEL, FLYING DEBRIS AND INJURING PEOPLE.  THE PRECURSOR OF 'FLYING CAR'. BEFORE THE "FLYING CAR", DIESEL ENGINES USUALLY EXHIBIT SYMPTOMS SUCH AS BLUE SMOKE, OIL BURNING, OR UNSTABLE ENGINE SPEED. AT THE BEGINNING, THE SPEED OF THE DIESEL ENGINE IS NOT CONTROLLED BY THE THROTTLE AND INCREASES SENSITIVELY UNTIL IT EXCEEDS THE RATED SPEED, AND THE ENGINE EMITS A LOT OF BLACK OR BLUE SMOKE. AT THIS POINT, IF INSENSITIVE MEASURES SUCH AS CUTTING OFF OIL, GAS, AND PRESSURE ARE USED TO OBSTRUCT THE ENGINE, THE ENGINE SPEED WILL CONTINUE TO RISE, AND A LOUD ROAR WILL BE ANNOUNCED. THE EXHAUST PIPE WILL BE FILLED WITH THICK SMOKE, AND THE SPEED WILL BE OUT OF CONTROL, WHICH WILL LEAD TO MAJOR ACCIDENTS SUCH AS CYLINDER RAMMING.